I purchased a Buffalo DriveStation Duo (HD-WL8TU3R1-EU 8TB) setup in RAID1 to have 4TB duplicated on two drives.
My first problem:
As I needed to give a copy of the content to a friend, I took out a drive and attempted to view the files on a computer via an external USB3.0 enclosure. To my surprise the computer would not see the drive. I am not sure if this is because the USB3.0 enclosure maybe isn't compatible with 4TB drives or if the drives are only viewable through Buffalo's RAID controller. Can anyone shed some light on this?
My second problem:
I ran out of space on the 4TB RAID1 and attempted to replace the 2x 4TB drives with 2 brand new drives in order to create another volume thinking I could exchange between the volumes. The Buffalo however thought both the new drives were degraded in RAID1. I was afraid to reinitialize them and reset the RAID1 as maybe the Buffalo would forget the setting of the original 4TB drives it had. My idea was to use the Buffalo Drivestation Duo as a RAID-1 enclosure basically and interchange the drives however this seems to not work! I will test this again once I have the content on the original 4TB backed up.
For your first problem:
As your drives are setup as a RAID configuration you can't just take a drive out and read the one drive on a pc like normal. Your best bet would be to take your drivestation to your friend and copy the data to your friends computer directly.
For the second problem:
It sounds like you want to swap between drives, if this is the case then you will need a different kind of filesever for that purpose, i.e one that supports hot swappable drives.
Thank you for the quick reply.
RE: Problem #1
My understanding of RAID1 is that it's a clone copy of the drives not using parity information like other RAID levels such as 5 or 6. Thus I thought you could just have two identical drives. So in theory if the Buffalo unit fails, but the disks are fine, I still can't read the data on the disks in a third party enclosure or directly on the motherboard because I need the unit itself?
RE: Problem #2
I would want to swap between BOTH drives together.. ie DRIVE A + B in RAID1 and DRIVE C + D also in RAID1 to have two separate volumes essentially using the Buffalo as a RAID-1 enclosure. It doesn't need to be hot swappable.
Called Buffalo Tech Support and "they didn't know" the answers to my questions. lol
See following link for more info on RAID1 and how to backup data: http://en.wikipedia.org/wiki/RAID_1#RAID_1
Note paragraph in the following link: RAID 1 has many administrative advantages. For instance, in some environments, it is possible to "split the mirror," declare one disk as inactive, do a backup of that disk, then "rebuild" the mirror. This is useful in situations where the file system must be constantly available. This requires that the application supports recovery from the image of data on the disk at the point of the mirror split. This procedure is less critical in the presence of the "snapshot" feature of some file systems, in which some space is reserved for changes, presenting a static point-in-time view of the file system. Alternatively, a new disk can be substituted so that the inactive disk can be kept in much the same way as traditional backup. To maintain redundancy during the backup process, some controllers support adding a third disk to an active pair. After the third disk rebuild completes, it is made inactive and backed up as described above.
For sure this is not the adequate "in some environments".
Yes it is possible, but very risky, unless you really really know what you are doing.